// Ultrasonic sensor setup
const int trigPin = 7;
const int echoPin = 6;

// LED pins for status indication
const int greenLEDPin = 9;
const int redLEDPin = 10;

void setup() {
  Serial.begin(9600);

  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(greenLEDPin, OUTPUT);
  pinMode(redLEDPin, OUTPUT);

  digitalWrite(greenLEDPin, LOW);
  digitalWrite(redLEDPin, LOW);
}

void loop() {
  // Read obstacle distance
  long duration, distance;
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  duration = pulseIn(echoPin, HIGH);
  distance = (duration / 2) / 29.1;

  // Obstacle avoidance
  if (distance < 100) { // If an obstacle is detected within 50 cm
    digitalWrite(greenLEDPin, LOW); // Stop indication
    digitalWrite(redLEDPin, HIGH);  // Stop due to obstacle
    Serial.println("Obstacle detected! Stopping.");
  } else {
    digitalWrite(greenLEDPin, HIGH); // Moving indication
    digitalWrite(redLEDPin, LOW);    // No obstacle
    Serial.println("No obstacle, moving.");
  }

  delay(1000); // Wait for a second before the next loop
}